InitState is the summary of references from the file named refer
SecondState is the summary of CSAPP and Computer Network https://www.bilibili.com/video/BV1JV411t7ow?spm_id_from=333.999.0.0&vd_source=5e8d719f8d97deb950e9f00e4688725c
以上均为个人总结，一些理解会很片面，欢迎各位大佬指出错误